Modification of\nthe Endoplasmic Reticulum to Enhance\nOvalbumin Secretion in <i>Saccharomyces cerevisiae</i>

Ovalbumin (OVA) is a high-quality protein for humans.\nModifying\nmicroorganisms to produce proteins offers a solution to potential\nfood protein shortages. In this study, OVA was expressed in <i>Saccharomyces cerevisiae</i>. Initially, screening signal peptides\nled to extracellular OVA reaching 3.4 mg/L using the INU1 signal peptide.\nCoexpressing Kar2 and PDI increased OVA production to 5.1 mg/L. Optimizing\nthe expression levels of regulators OPI1, INO2, and INO4 expanded\nthe endoplasmic reticulum membrane, raising yield to 5.5 mg/L. Combining\nboth strategies increased OVA production to 6.2 mg/L, 82% higher than\ncontrol. This strategy also enhanced secretion of other proteins.\nFinally, fed-batch fermentation in a 3-L bioreactor significantly\nboosted OVA production to 116.3 mg/L. This study provides insights\nfor the heterologous synthesis of other high-quality proteins for\nfuture food applications.